What’s Vulnerable › Vulnerabilities

CVE-2025-66565: Fiber Utils UUIDv4 and UUID Silent Fallback to Predictable Values

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-09 · updated 2026-10-07
• Weakness: CWE-252

Description

Fiber Utils is a collection of common functions created for Fiber. In versions 2.0.0-rc.3 and below, when the system's cryptographic random number generator (crypto/rand) fails, both functions silently fall back to returning predictable UUID values, including the zero UUID "00000000-0000-0000-0000-000000000000". The vulnerability occurs through two related but distinct failure paths, both ultimately caused by crypto/rand.Read() failures, compromising the security of all Fiber applications using these functions for security-critical operations. This issue is fixed in version 2.0.0-rc.4.

Affected products

• gofiber utils: through 1.2.0; 2.0.0-beta1, 2.0.0-beta10, 2.0.0-beta11, 2.0.0-beta12, 2.0.0-beta13, 2.0.0-beta14 (+12)

References

• https://github.com/gofiber/utils/commit/6c6cf047032b9c8dff43d29f990b4b10e9b02d47
• https://github.com/gofiber/utils/security/advisories/GHSA-m98w-cqp3-qcqr
• https://github.com/gofiber/utils/security/advisories/GHSA-m98w-cqp3-qcqr

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